Keyword aliases

Date:Sun Apr 16 10:18:47 2017
You can now define "keyword aliases" that let you alias specific mob/obj/exit
keywords using "alias %<keyword> <expansion>":

  > l ba
  You don't see a ba.
  > alias %ba barliman                   <=== note the "%"
  > l ba
  A fairly short man, Barliman Butterbur ...

You can force-inhibit the expansion by prefixing a keyword in a "normal"
command using "%":

  > l %ba
  You don't see a ba.

It's somewhat likely that a few commands won't work correctly with keyword
aliases. Please report any bugs :)

Thanks Rashnak for the idea!

- Dáin